I'd give the turtlenecks Inhuman Strength, Aquatic, and Supernatural Sense to cover their sonar, plus a decent Guns score. The shark-gorilla thingies from Even Hand would probably get Inhuman Strength and Toughness, Claws, and Aquatic.
As for Formor casters, I'd create a new sort of Sponsored Magic which is unaffected by running water and grants entropomantic evothaum and perhaps bonuses to entropomancy and biomancy. Then just throw in a few of Inhuman Strength, Speed, Toughness, and Recovery, add Aquatic and some Supernatural Senses, and maybe some Refinement. Skill up and you're good to go!